Boat hull



H. J. DORNAK BOAT HULL 2 Sheets-Sheet 1 Filed Feb. 11, 1960 R. m k am nwm a J. m z U A Nut mm mm m m 9 H m mm fvw mm m mm -1 Q mm mm mm vw Q mmvm an mm RE w H. J. DORNAK Feb. 12, 1963 BOAT HULL 2 Sheets-Sheet 2Filed Feb. 11, 1960 Henry 5/. Dorna/r INVENTOR.

BY flaw 8% all This invention relates to a novel and useful hullconstruction, and more particularly to a hull construction utilizing aplurality of longitudinally extending concave tunnels which arespecifically adapted to increase speed, safety, stability andperformance as well as affording a smoother ride and increasing theplaning characteristics of a hull to reduce the draft of the latterwhile moving at high speeds.

The multi-tunneled hull construction includes at least threelongitudinally extending concave tunnels formed on the bottom surfacesof the hull with two additional side air tunnels being formed along theupper edges of the sides of the hull for increasing the stability of thelatter while travelling at high speeds.

Various types of hull designs have been heretofore devised foraccomplishing the utmost in speed, safety, and stability as well assmooth riding characteristics. Many of these prior hull designs haveincluded means for entrap ping air in concave or recessed tunnels andthe like along the bottom surfaces of the hull whereby the ridingcharacteristics and the speed of the hull will be appreciably increased.Most of these previous designs of hull structures have p-roven to beundesirable in one way or another and the hull construction comprisingthe present invention has been specifically adapted to eliminate anystructural features which could be considered undesirable such asexcessive wetted area in the region of the hull contacting the waterwhen the hull is travelling at high speeds.

The hull comprises an aft portion and a forward portion with the tunnelsformed in both portions with those in the aft portion being continuouswith corresponding tunnels of the forward portion of the hull. Theportions of the tunnels disposed on the aft portion of the hull extendsubstantially parallel to the longitudinal center line of the hull andthe portions of the tunnels formed in the forward portion of the hullare inwardly converging and upwardly curving toward the bow of the hull.The tunnels are each defined by depending cut-waters disposed along theopposite longitudinal edges of the tunnels with the tunnels spacedtransversely of the hull immediate adjacent each other. The cut-watersformed on the forward hull portion are formed by a series of threereversing curves and the cut waters gradually taper rearwardly into twodepending downwardly convergent straight surfaces disposed atsubstantially 90 to each other. Further, the cut-waters decrease intheir vertical extent gradually from the forward portion of the bull tothe aft portion thereof whereby the tunnels are decreased in depth fromtheir forward ends to their rearward ends with the forward ends beingsubstantially arcu-ate in cross section and their rearward ends beingrelatively shallow and inverted U-shaped in cross section.

The main object of this invention is to provide a hull structure whichwill closely approach the ultimate in speed, safety and stability whilestill maintaining an extremely smooth ride and hull having a shallowdraft. Various types of hull structures have been heretofore designedfor obtaining maximum speed, but these hull structures have proven to belacking in stability, safety and smooth riding characteristics.

A further object of this invention, in accordance with the precedingobject, is to provide a hull structure which will afford the maximum inspeed with a propulsion unit of a given horsepower while maintainingwater spray at a minimum.

rate area I 4 H I in scribed and claimed, reference being had to theaccompanying drawings forming a part hereof, wherein like numerals referto like parts throughout, and in which:

FIGURE 1 is a bottom plan view of the hull construction comprising theinstant invention;

FIGURE 2 is a side elevational view of the hull construction illustratedin FIGURE 1;

FIGURE 3 is a rear elevational view of the hull construction;

FIGURE 4 is a front elevational view of the hull construction showingmore clearly the details of the configuration of and the relativepositioning of the tunnels;

FIGURE 5 is a vertical transverse sectional view taken substantiallyupon the plane indicated by the section line 55 of FIGURE 2;

FIGURES 6 and 7 are rear elevational views of the hull constructionsimilar to that of FIGURE 3 showing the manner in which the hullconstruction is particularly well adapted for both dual and singlepropeller installations.

Referring now more specifically to the drawings the numeral 10 generallydesignates the hull construction of the present invention which includesan aft portion 12 and a forward or how portion 14. The hull constructionit} includes bottom surfaces 18 and side surfaces 20 which aresubstantially straight relative to their longitudinal length throughoutthe extent of the aft portion 12 of the hull construction it). The sidesurfaces 2d of the forward or how portion 14 are inwardly convergenttoward the forward end of the hull l0 and the bottom surfaces 18 of theforward or bow portion 14 are upwardly curved toward the bow of the hullit The bottom surfaces 18 on the aft portion 12 of the hull construction10 have a plurality of concaved tunnels i6, 22 and 24 formed therein.The tunnel 16 is formed along the longitudinal centerline of the hull itwhile a pair of tunnels 22 are disposed on opposite sides of and extendparallel to the tunnel 16. Further, the bottom surfaces 18 of the hullconstruction ll] are also provided with a pair of tunnels 24 which aredisposed immediately adjacent and outwardly of the tunnels 22 and alsoextend substantially parallel to the longitudinal centerline of the hullconstruction 10. Each of the tunnels lo, 22 and 24 extend into theforward or bow portion 14 of the hull and curve upwardly as can be mostclearly seen from FlGURE 2 of the drawings.

The tunnels 16, 22 and 2.4 are disposed immediately adjacent each otherand defined by depending and longitudinally extending cut-waters 26which are disposed between adjacent tunnels and along the remotelongitudinal side edges of the outermost tunnels 24. The cut-waters 25in the forward portion 14 of the hull construction 10 are formedgenerally by a series of three transversely extending reversely curvingsurfaces extending longitudinally of said hull which gradually tapertoward the rear of the aft portion 12 of the hull construction It andmerge into a pair of downwardly converging straight surfaces disposed atsubstantially to each other.

The cut-waters 26 have a relatively great vertical extent in the forwardportion 14 of the hull 10 and gradually taper rearwardly decreasing invertical extent as they taper into the inclined and converging straightsurfaces 28. Inasmuch as the cut-waters 26 decrease in vertical extenttoward the rear end of the aft portion 12 of the hull construction it itwill be noted from a comparison between smegma FIGURES 3 and 5 that thetunnels in, and 2d are substantially arcuate in cross-section in theforward portion 14 of the hull construction 1d and that they taper torelatively shallow inverted U-shaped tunnels toward the rear of the aftportion 12.

It is to be understood that the hull construction is adapted to plane onrelatively calm water with substantially its entire forward or bowportion 14 out of the water. The tunnels 16, 22 and 24 of the aftportion as well as the cut-waters 26 formed on the aft portion 12 extendsubstantially parallel to the longitudinal center line of the hullconstruction so that the drag of the wetted surfaces of the hullconstruction will be maintained at a minimum. The hull construction Itis therefore substantially as broad at its rear end as it is at itsmaximum beam and therefore the drag of the hull construction it on thewater is maintained at a minimum.

It is of course to be noted that the tunnels 16, 22 and 2/4 in the aftportion 12 of the hull construction it are continuous with correspondingtunnels formed in the forward or bow portion 1 so that smooth unbrokenplaning surfaces are provided.

The upper edges of each of the side surfaces 2% have an outwardlyprojecting and horizontally disposed flange 30 extending therefrom whichterminates at its free outer end in a downturned substantially verticalflange 32. The flanges 3t and 32 formed along the upper edges of each ofthe side surfaces 20 form an air tunnel 34 which is adapted to affordadditional stability to the hull construction While travelling at highspeeds. Further, the tunnel 34 also provides a means for downwardlydeflecting any water spray caused by the movement of the hullconstruction 10 through water. In operation, while the hull 10 istravelling over the surface of a body of water at relatively highspeeds, the tunnels 16, 22 and 24 entrap air which then passes betweenthe cut-waters 26 under the hull it As the air entrapped by the tunnelsmoves under the aft portion 12 of the hull 10 it forms thin wide ribbonsof compressed air over which the hull 16 rides. The air entrapped underthe aft portion 12 of the hull 10 not only increases the smooth ridingcharacteristics but also greatly reduces the friction between the wettedarea of the hull It and the water over which it is travelling. Stillfurther the cut-waters 26 provide extreme stability to the construction16 while executing sharp turns at high speeds and if it is desiredadditional cut-waters 36 may be provided in the aft portion 12 of thetunnels 24 to further increase the stability of the hull it? whileexecuting sharp turns at high speeds. Each of the cut waters 26 and 36greatly reduce the tendency of the hull to slide laterally during highspeed turns.

The cut-waters 26 formed on the forward or bow portion 14 of the hull itcut into the water to break up any waves which may be present. The forceof the waves is therefore greatly depleted and the result is a muchsmother ride and less wear and tear on the hull 10 caused byoverstressing the components of the hull it by hitting solid waves atrelatively high speeds.

The hull construction, being provided with the tunnels 16, 22 and 24defined by the cut-waters 26, is able to navigate in relatively heavyseas at substantial speeds wtihout undue pounding and without dartinfrom one side to the other while encountering waves from either quarter.

Attention is now directed to FIGURES 6 and 7 of the drawings wherein itwill be noted that the hull construction 1% is particularly well adaptedfor dual propeller installations as well as single propellerinstallations. If the hull construction ill is to be provided with dualpropeller installation the two propellers are disposed in verticalalignment with the tunnels 22 while a single installation propeller isdisposed in vertical alignment with the center tunnel 16.

The aligning of the propellers 38 with certain of the tunnels insuresthat the water through which the propellers will pass will be relativelycalm and not extremely turbulent. The tunnels also enable the propellers35 to be positioned closer to the surface of the water passing bene ththe hull it} which, in the case of outboard motors, enables a lesserportion of the lower unit of the outboard motor or motors to besubmerged in the water which reduces the drag and therefor increase thespeed of the hull lb.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In a marine craft, a hull, said hull including an aft portion havingsubstantially straight longitudinally extending bottom and side surfacesand a forward portion defining a bow with inwardly converging sidesurfaces and upwardly curving bottom surfaces, said aft and forwardbottom and side surfaces being continuous to form smooth unbrokenlongitudinally extending surfaces, at least three longitudinallyextending, transversely spaced and substantially parallel concavetunnels formed in said aft bottom surfaces defined by dependinglongitudinally extending cut-waters disposed between adjacent tunnelsand along the remote longitudinal edges of the outermost tunnels, saidcut-waters each being substantially wedge shaped in transversecross-section, said tunnels terminating in said forward portion ininwardly converging and upwardly curving forward tunnels disposed inside-by-side relation with their forward ends open to receive airfunneled thereinto, corresponding fore and aft tunnels being continuoussaid tunnels formed on said aft portion being substantially arcuate incross-section and tapering gradually rearwardly decreasing in depthforming relatively shallow inverted U-shaped tunnels wherein air will beentrapped in said tunnels arcuate in cross-section and will pass underthe aft portion of said bull to cushion the ride of the hull through thewater and reduce friction to a minimum.

2. The combination of claim 1 wherein said cut-waters in said forwardhull portion are each formed by three successive transversely extendingreversely curving longitudinally extending surfaces which graduallytaper into two downwardly convergent straight surfaces disposed atsubstantially 96 to each other at the rear end of said aft portion ofsaid hull;

3. In a marine craft, a hull, said hull including an aft portion havingsubstantially straight longitudinally extending bottom and side surfacesand a forward portion defining a bow with inwardly converging sidesurfaces and upwardly curving bottom surfaces, said aft and forwardbottom and side surfaces being continuous to form smooth unbrokenlongitudinally extending surfaces, at least three longitudinallyextending, transversely spaced and substantially parallel concavetunnels formed in said aft bottom surfaces defined by dependinglongitudinally extending cutwaters disposed between adjacent tunnels andalong the remote longitudinal edges of the outermost tunnels, saidcut-waters each being substantially wedge shaped in transversecross-section, said tunnels terminating in said forward portion ininwardly converging and upwardly curving forward tunnels, correspondingfore and aft tunnels being continuous, one of said tunnels extendingsubstantally the entire length of said hull along its longitudinalcenter line with the other two tunnels disposed on opposite sidesthereof, each of the aft portions of said tunnels being of a widthadapted to span the diameter of a marine propeller whereby a singlepropeller may be aligned with said one tunnel nad a dual motorinstallation may have its two propellers aligned with said other twotunnels.

4. The combination of claim 3 including fourth and fifth tunnels formedin said hull and disposed immediately adjacent and outwardly of saidother two tunnels which each terminate at the outer longitudinal edgesalong the lower edges of said side surfaces.

5. The combination of claim 4 including a longitudinally extendingcut-water formed in the center of the portions of said fourth and fifthtunnels disposed on the aft portion of said hull to increase thestability of the latter during high speed turns and to reduce thetendency of the hull to slide laterally during high speed turns.

6. In a marine craft, a hull, said hull including an aft portion havingsubstantially straight longitudinally extending bottom and side surfacesand a forward portion defining a bow with inwardly converging sidesurfaces and upwardly curving bottom surfaces, said aft and forwardbottom and side surfaces being continuous to form smooth unbrokenlongitudinally extending surfaces, at least three longitudinallyextending, transversely spaced and substantially parallel concavetunnels formed in said aft bottom surfaces defined by dependinglongitudinally extending cut-waters disposed between adjacent tunnelsand along the remote longitudinal edges of the outermost tunnels, saidcut-waters each being substantially wedge shaped in cross section, saidtunnels terminating in said forward portion in upwardly curving forwardtunnels disposed in spaced side-by-side relation with their forward endportions open to receive air funneled thereinto, corresponding fore andaft tunnels being continuous, one of said tunnels extendingsubstantially the entire length of said hull along its longitudinalcenter line with the other two tunnels disposed on opposite sidesthereof, each of the aft portions of said tunnels being of a width.adapted to span the diameter of a marine propeller whereby a singlepropeller may be aligned with said one tunnel and a dual motorinstallation may have its two propellers aligned with said other twotunnels.

References Cited in the file of this patent UNITED STATES PATENTS D.160,027 Smith Sept. 5, 1950 359,861 Hanlen Mar. 22, 1887 649,525 NicholMay 15, 1900 1,189,227 Baker July 4, 1916 2,234,899 Higgins Mar. 11,1941 2,366,590 Brownback Ian. 2, 1945 2,515,005 Hickman July 11, 19502,875,720 Hupp Mar. 3, 1959 2,938,490 Martin May 31, 1960 FOREIGNPATENTS 2,292 Great Britain 1903 571,365 Great Britain Aug. 21, 1945

1. IN A MARINE CRAFT, A HULL, SAID HULL INCLUDING AN AFT PORTION HAVINGSUBSTANTIALLY STRAIGHT LONGITUDINALLY EXTENDING BOTTOM AND SIDE SURFACESAND A FORWARD PORTION DEFINING A BOW WITH INWARDLY CONVERGING SIDESURFACES AND UPWARDLY CURVING BOTTOM SURFACES, SAID AFT AND FORWARDBOTTOM AND SIDE SURFACES BEING CONTINUOUS TO FORM SMOOTH UNBROKENLONGITUDINALLY EXTENDING SURFACES, AT LEAST THREE LONGITUDINALLYEXTENDING, TRANSVERSELY SPACED AND SUBSTANTIALLY PARALLEL CONCAVETUNNELS FORMED IN SAID AFT BOTTOM SURFACES DEFINED BY DEPENDINGLONGITUDINALLY EXTENDING CUT-WATERS DISPOSED BETWEEN ADJACENT TUNNELSAND ALONG THE REMOTE LONGITUDINAL EDGES OF THE OUTERMOST TUNNELS, SAIDCUT-WATERS EACH BEING SUBSTANTIALLY WEDGE SHAPED IN TRANSVERSECROSS-SECTION, SAID TUNNELS TERMINATING IN SAID FORWARD PORTION ININWARDLY CONVERGING AND UPWARDLY CURVING FORWARD TUNNELS DISPOSED INSIDE-BY-SIDE RELATION WITH THEIR FORWARD ENDS OPEN TO RECEIVE AIRFUNNELED THEREINTO, CORRESPONDING FORE AND AFT TUNNELS BEING CONTINUOUSSAID TUNNELS FORMED ON SAID AFT PORTION BEING SUBSTANTIALLY ARCUATE INCROSS-SECTION AND TAPERING GRADUALLY REARWARDLY DECREASING IN DEPTHFORMING RELATIVELY SHALLOW INVERTED U-SHAPED TUNNELS WHEREIN AIR WILL BEENTRAPPED IN SAID TUNNELS ARCUATE IN CROSS-SECTION AND WILL PASS UNDERTHE AFT PORTION OF SAID HULL TO CUSHION THE RIDE OF THE HULL THROUGH THEWATER AND REDUCE FRICTION TO A MINIMUM.